This invention relates to metal parts assembly rivets, and is directed particularly to a screw lock rivet for sheet metal parts, including a rivet portion for riveting to one member of a pair of companion work-pieces to be assembled, and a screw lock portion adapted to be received in an adjustment slot of the other work-piece to enable positionally adjusted attachement thereto in the field simply by turning the rivet head portion approximately 90 circular degrees with use of a socket wrench or the like. Rivets, nuts and bolts, and sheet metal screws are commonly used in the assembly of sheet metal parts. Ordinarily, if assembly is completed at the factory and subsequent disassembly during use is not anticipated, rivets will be used because of their low cost, ease of installation with power tools, effectiveness, and durability. Where sheet metal or metal plate parts or work-pieces are only partially assembled at the factory, to be adjustably assembled to one another in the field during installation, nuts and bolts are most often used. For example, in the installation of prefabricated roller guide tracks for overhead sliding garage doors, upon installation in the field the roller guide tracks are usually bolted to support brackets attached to the garage door frame-work. In such instances, to provide for positional adjustment of the roller guide tracks, the bolt openings in the supporting brackets are elongated or in the form of a slot. The use of field assembly nuts and bolts for such purposes is not only tedious and expensive as compared to the cost of riveting, but also entails the use of loose nuts and bolts that must be separately accounted for during shipment and installation.